Abstract: A system for selecting accompaniment patterns in accordance with which accompaniment musical tones are produced in an electronic musical instrument. The system includes a memory for storing a plurality of accompaniment patterns. A plurality of storage devices corresponding respectively to a plurality of operable members is provided. A select device is operable to select one of the accompaniment patterns to produce pattern identification data indicative of the selected accompaniment pattern. A writing device is responsive to an operation of any one of the operable members for writing the pattern identification data into one of the storage devices corresponding to the operated one operable member, thereby assigning the selected accompaniment pattern to the one operable member. A reading device is responsive to an operation of the one operable member for reading from the memory the selected accompaniment pattern.